East German Pat. No. 67,130 to Becker et al. describes a procedure for the synthesis of 3,5-disubstituted-1,2,4-triazoles useful as intermediates. The product triazoles are formed as follows. A starting material of structure I ##STR2## wherein R.sub.1 is alkyl, aryl, aralkyl, alkoxyalkyl, acylaminoalkyl, or a heterocyclic group and R.sub.2 is hydrogen, alkyl, or aryl, is treated with acylating agent, such as an acid chloride or acid anhydride or an alkylating agent, such as an alkylhalide. Depending on conditions, the product is isolated directly (or as its salt) or an intermediate product or residue of undefined structure or composition is first isolated and then converted to the triazole product by thermolysis or hydrolysis. A by-product is described in several examples which is a diacyl (or dialkyl) hydrazine presumably arising from the 1,2-hydrazino portion of the starting thiazole that is lost in the course of the reaction.
In Example 10 of the Becker et al. patent, N-4-(3,5-dimethyl-1,2,4-triazolyl)benzamidine is reacted with acetic anhydride at 170.degree. C. for 2-3 hours with evaporation of the volatile materials to form a residue ("Ruckstand") of unknown composition and utility. The residue is heated for 3 hours in water to give the 3-methyl-5-phenyl-1,2,4-triazole product.
Becker et al neither identify the components of the residue nor separate out or isolate such components. However, it is believed that about one-half of the Ruckstand or residue is a mixture of various by-products, and the remainder is a mixture of 1-acetyl-5-methyl-3-phenyl-1H-1,2,4-triazole and 1-acetyl-3-methyl-5-phenyl-1H-1,2,4-triazole in about a 90:10 ratio to each other.
Becker et al. in a paper entitled "A Novel Synthesis for 3-Substituted 1,2,4-Triazoles," Journal fur praktische Chemie. Volume 311, 1969, pages 477-489, disclose the preparation of 3-substituted-1,2,4-triazoles including 3-phenyl-1,2,4-triazoles of the structure ##STR3## wherein R.sup.1 can be ethoxy, methyl, ethyl or n-propyl. A general preparation for 1-acetyl-3-phenyl-1,2,4-triazole and 1-propionyl-3-phenyl-1,2,4-triazole is set out on page 487.
U.S. Pat. No. 4,006,159 to Newman discloses mixtures of acyl-substituted 1,2,4-triazole-3-carboxamides which may be presented by the following structural formulae: ##STR4## wherein each mixture consists of all three forms wherein R is the same in each form and wherein R is hydrogen, alkyl having up to 15 carbon atoms; cycloalkyl having from 3 to 8 carbon atoms; phenyl; ortho-, meta-, or para-hydroxyphenyl; ortho-, meta-, or paramethoxyphenyl; or adamantyl. The above mixture is said to be useful as anti-viral agents.
Ikizler et al Chem. Abstracts, Vol. 86, Abstract No. 55351w (1977) discloses the preparation of triazoles of the structure ##STR5## wherein R.sup.1 is acetyl, and R is 4-CH.sub.3 C.sub.6 H.sub.4, 3-O.sub.2 NC.sub.6 H.sub.4 - or 2-naphthyl. No utility is given for such compounds.
British Specification No. 1,351,430 discloses triazoles of the formula ##STR6## wherein R and R.sub.1 are phenyl or substituted phenyl though not both simultaneously phenyl, and R.sub.2 is hydrogen or C.sub.1 -C.sub.4 alkyl, which are said to be useful as CNS depressants.
U.S. Pat. No. 4,169,148 discloses a method of treating inflammatory and/or psychotic conditions with derivatives of 1,2,4-triazoles having the structure ##STR7## wherein R and R.sup.1 may be the same or different and may be lower alkyl, cycloalkyl, cycloalkyl-lower alkyl, phenyl or phenyl-lower alkyl. Where present, the phenyl whether alone or as part of a lower alkyl group may be substituted with one or two of halogen, trifluoromethyl, lower alkyl, lower alkoxy or lower alkylthio.
U.S. Pat. No. 4,154,841 discloses 1-acyl-3(5)-alkyl-5(3)-phenyl-1,2,4-triazoles which are useful as antiinflammatory agents and have the structure ##STR8## wherein R is lower alkyl or cycloalkyl, R.sup.1 is lower alkyl or cycloalkyl, and X is hydrogen, halogen, lower alkyl, lower alkoxy, nitro or trifluoromethyl.
The carbinolamine esters of 1,2,4-triazoles of the invention which are useful as antiinflammatory agents have the structure ##STR9## wherein R is lower alkyl, cycloalkyl, cycloalkyl-lower alkyl, phenyl or phenyl-lower alkyl. The phenyl may be substituted with one or two halogen, trifluoromethyl, lower alkyl, lower alkoxy or lower alkylthio groups.
R.sup.1 may be lower alkyl, phenyl-lower alkyl, cycloalkyl or cycloalkyl-lower alkyl; PA1 R.sup.2 may be hydrogen, lower alkyl, cycloalkyl, phenyl or phenyl substituted with any of the above substituents; and PA1 R.sup.3 may be lower alkyl, cycloalkyl, phenyl or phenyl substituted with any of the above substituents.
The preferred compounds of the invention are those of formula I wherein R.sup.1, R.sup.2 and R.sup.3 are lower alkyl and R is phenyl or substituted phenyl.
The term "lower alkyl" as used herein refers to alkyl groups having 1 to 7 carbons, preferably 1 to 4 carbons, including straight or branched chain groups, such as methyl, ethyl, n-propyl, i-propyl, 2-propylbutyl, n-butyl, s-butyl, i-butyl, t-butyl, n-pentyl, n-hexyl, and n-heptyl and the various branched chain isomers thereof.
The terms "lower alkoxy" and "lower alkylthio" as used herein refers to lower alkyl groups as defined above attached to an oxygen atom or sulfur atom, respectively, with methoxy being preferred.
The term "cycloalkyl" as used herein refers to saturated carbocyclic radicals containing 3 to 7 carbons in the ring, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl.
The term "halogen" as employed herein refers to chlorine, bromine, iodine or fluorine with chlorine and bromine being preferred.
The compounds of formula I of the invention may be prepared by sequentially treating a 1,2,4-triazole of the structure ##STR10## (prepared as described in U.S. Pat. No. 4,169,148) with an organic base, such as a tertiary amine, for example, triethylamine or N-methylmorpholine, treating the mixture with an aldehyde of the structure ##STR11## and then finally treating the reaction mixture with an acylating agent of the structure ##STR12## wherein X is Cl or Br, in the presence of an inert solvent, such as 1,2-dimethoxyethane, ether, tetrahydrofuran, dioxane, toluene and the like, to form compounds of formula I.
The compounds of formula I have antiinflammatory activity as measured by the mouse active arthus (MAA) test and/or other related tests and are useful as antiinflammatory agents and may be used, for example, in a manner similar to phenylbutazone or indomethacin. They may be used to decrease joint swelling, tenderness, pain and stiffness in mammalian species, e.g., in conditions such as rheumatoid arthritis. The quantity administered ranges from about 1 mg to about 150 mg per kg and preferably from about 5 mg to about 75 mg per kg of body weight per day.
A compound of formula I can be administered orally or parenterally (for example, intraperitoneally, subcutaneously, intramuscularly or intravenously). Powders can be prepared by comminuting the active ingredient with a similarly comminuted diluent, such as starch or lactose. Suitable forms for oral administration include capsules, tablets, troches, elixirs, wafer, chewing gum, syrups, and a suitable form for parenteral administration is a sterile injectable. Such unit dosage forms are prepared by compounding with a conventional vehicle, excipients, binders, preservatives, stabilizers, flavoring agents or the like as called for by acceptable pharmaceutical practice. Also, the compounds used in this invention can be formulated with other pharmaceutically active compounds.
The tablets, troches, pills, capsules and the like may also contain the following: a binder, such as gum tragacanth, acacia, corn starch or gelatin; an excipient, such as dicalcium phosphate, a disintegrating agent, such as corn starch, potato starch, alginic acid and the like; a lubricant, such as magnesium stearate; and a sweetening agent, such as sucrose, lactose or saccharin may be added or a flavoring agent, such as peppermint, oil of wintergreen or cherry flavoring. When the dosage unit form is a capsule, it may contain in addition to materials of the above type a liquid carrier, such as a fatty oil. Various other materials may be present as coatings or to otherwise modify the physical form of the dosage unit, for instance, tablets, pills or capsules may be coated with shellac, sugar or both. A syrup or elixir may contain the active compounds, sucrose as a sweetening agent, methyl and propyl parabens as preservatives, a dye and a flavoring, such as cherry or orange flavor. Of course, any material used in preparing any dosage unit form should be pharmaceutically pure and substantially non-toxic in the amounts employed.